1. Field of the invention
This invention relates to modular cabana panels of the type having metal skins that cover the top and bottom surfaces of an expanded polystyrene core. More particularly, it relates to snap lock designs that facilitate the construction of a roof or wall with said panels.
2. Description of the prior art
Roofs or walls made of expanded polystyrene (EPS) modular panels are popular in the construction industry because they insulate well, are light in weight, and are easy to install because of their modular form.
EPS is a soft, easily damaged material. Accordingly, the top and bottom surfaces of the EPS core are usually covered by a thin skin of sheet metal; the sheet metal is bonded to the core by a suitable adhesive means. The metal sheets protect the core from abrasion and, advantageously, contiguous edges thereof may be bent into complementally interlocking forms to provide a means for interlocking abutting edges of the panels.
In many designs, the edges of the EPS core are also sculpted to provide supplemental interlocking means. In those designs, a groove may be formed in the edge of one panel and a corresponding tongue may be formed in the edge of an abutting panel. Thus, in a typical roof made of interlocked modular panels of the metal skin-covered EPS type, both the abutting foam cores and the contiguous metal skins are interlocked with one another.
All of the designs are intended to facilitate the interlocking of the panels at the time the roof is laid down, and to provide as near a seamless fit as possible to inhibit to the greatest extent possible the intrusion of moisture into the space between the panels. However, most contractors use a caulking compound to seal the seam between the panels, regardless of how tightly fit together the contiguous interlocking panels are believed to be.
Caulking compound, however, does a poor job of sealing deep, narrow cracks, and rapidly deteriorates when exposed to sunlight. In the panel installations heretofore known, the caulking compound is used to seal such cracks and is exposed to sunlight; thus, the sealing is often ineffective. Thus there is a need for a panel interlocking design that does not create narrow, deep cracks and which shields the caulking compound from sunlight.
Another problem in the industry stems from the method used to adhere the metal skins to the foam cores; after adhesive is applied to the core, means are employed to press the metal skins thereagainst while the adhesive cures. Due to the viscosity of the adhesive, there is a low coefficient of friction between the skins and the cores; thus, the skins slip easily and it is difficult to maintain the desired alignment between skin and core. Numerous anti-slipping devices have been created to deal with this problem, but the most common technique is to place a straight board on the edge of the foam and to align the metal skin against it. This involves means for holding the board as well; the technique works, but it adds expense to the panel manufacturing process.
Accordingly, there is also a need for a panel design that facilitates the step of gluing the skins to the core by eliminating the need to employ alignment tools during the adhesion process.
Despite the many attempts heretofore made, there also remains a need for an interlocking panel construction that is easy to lock and which inhibits moisture penetration. More particularly, there remains a need for an interlocking panel design that is structurally simple so that it can be mass produced at low cost yet which is durable and effective.
There is also a need for a versatile design that is easily modified to produce: 1) a very stiff, almost inflexible interconnection means so that the panels are snap fit together only when considerable force is used; 2) a very flexible interconnection means so that the panels are snap fit together when a very light force is used; and 3) an infinite number of interconnection means of varying degrees of flexibility therebetween.
The prior art, considered as a whole, neither teaches nor suggests to those of ordinary skill how the needed cabana panels could be provided.